This is an application from University of Pennsylvania School of Medicine faculty to participate in the planned Transfusion Medicine/Hemostasis Clinical Trial Network. This group includes the resources of the University of Pennsylvania Health System (UPHS), the Children's Hospital of Philadelphia (CHOP) and the Penn-Jersey Division of the American Red Cross (PJ-ARC). UPHS and CHOP have ongoing large collaborative programs led by Barbara A. Konkle, M. D., the P.I. of this application, and Catherine Manno, M.D., a co-investigator, respectively, for the care of patients with inherited and acquired disorders of hemostasis. These programs have a long-standing record of participation in clinical trials. In addition, the institutions provide transfusion services, including the provision of cellular components and plasma, to large pediatric and adult bone marrow and stem cell transplantation programs, liver transplantation programs and trauma programs, among other specialized programs. The transfusion services provide plasmapheresis for disorders such as thrombotic thrombocytopenic purpura. Scott Murphy, M.D., a co-investigator in this proposal, lends his experience in clinical trial networks in hematology, having been a long standing member of the Polycythemia Vera study group and an internationally recognized expert in platelet transfusion. Dr. Murphy, a faculty member of the University of Pennsylvania is the Medical Director of the PJ-ARC. Two randomized clinical trials are proposed: 1) Comparision of Platelet Concentrates Derived from Platelet Rich Plasma and Buffy Coats and, 2) Anticoagulation with Unfractionated Heparin Versus the Direct Thrombin Inhbitor Argatroban and the Risk of Thrombosis, Thrombocytopenia and Adverse Clinical Outcomes Following Cardiopulmonary Bypass Surgery. The University of Pennsylvania can provide extensive resources for this Network including patients for enrollment and experience in clinical trial design and enrollment. The investigators look forward to the opportunity to actively participate in such a network which will significantly advance the care of children and adults requiring transfusion or suffering from inherited or acquired disorders of hemostasis.